Non-conventional geoelectric arrays : practical results of the OTKA project K49604

In this paper we provide a comprehensive summary about the practical results of the OTKA project K49604. 1. We calculated the consequences of incorrect positioning of the electrodes for various multielectrode systems. In practice these effects were found to be negligible. The only exception is the case of rocky surface, where it is impossible to put the electrodes in the desired positions. The errors can however be kept within an acceptable range, if the electrodes of the linear arrays are put off-set, at right angles from the measuring line. A five-six times larger off-set has less effect than a certain mis-position along the line, connecting the electrodes. 2. We carried out tensorial geoelectric measurements around the Cistercian Monastery at Pilisszentkereszt. Areal measurements provide much more detailed and unambiguous anomalies than 2D profile measurements, and the tensor invariant representation of apparent resistivity anomalies provides a realistic picture about the lateral variation of the subsurface resistivity, even in field circumstances. 3. We tested the applicability of 3D electrical resistivity tomography (ERT) technique to detect landmines in different soil conditions and at various depths. Metallic and non-metallic landmines buried in wet and dry soils had been synthetically modeled. According to the inverted resistivity data using the dipole axial array in wet environment, it was possible to locate the metallic and non-metallic landmines as long as the noise level was about 5%. 4. We elaborated moreover a geoelectrical procedure which is able to map multidirectional fissure systems by combining geoelectrical profiling and geoelectrical azimuthal measurements. Results received by using both the so-called null-, and traditional arrays were jointly interpreted. The humidity of the fissures affects the measured results significantly, and in a meaningful way. 5. We presented the socalled standardized pricking probe (PP) surveying technique and demonstrated its usefulness in an archaeological study. The PP images proved to be definitely more close to the realistic shape of the buried chapel than the geoelectric and magnetic measurements, and they also revealed more details about the subsurface than the georadar. The optimum PP parameters: horizontal interval, pricking depth, observable quantity and its way of presentation were optimized through field experiments. For more details see the cited publications. The figures ever published in Hungarian journals are not reproduced here. Keywords: 3D ERT; geometric nois